Van Polen feels the 17 year-old defender will continue to develop.
He told De Stentor: "I always say: If you are not a (Leo) Messi, do not count on your talent. The career of young players is not only going up. Can you fight back with the setbacks you get?
"Liverpool is an incredibly beautiful club. Once you go there, you will be assured of being part of a great club for the rest of your career. You will make good financial progress and you develop between those good players also quickly.
"If he continues to develop, they will be delighted. If not they'll discard him."